Tilting mechanism for tractor loaders



Sgept. 29, 1953 LE GRAND H. LULL TILTING MECHANISM FOR TRACTOR LOADERS 3Sheets-Sheet 1 Filed April 5, 1950 N mlNn l r zaknvp fl. (0..

5 Sheets-Sheet 2 LE GRAND H. LULL TILTING MECHANISM FOR TRACTOR LOADERSSept. 29, 1953 Filed April 3, 1950 P 29, 1953 LE GRAND H. LULL TILTINGMECHANISM FOR TRACTOR LOADERS 3 Sheets-Sheet 3 Filed April 3, 1950Patented Sept. 29, 1953 UNITED STATES PATENT OFFICE TILTING MECHANISMFOR-TRACTOR LOADERS 4 Claims.

This invention relates generally to improvements in tractor mountedmaterial loaders and shovels of the general type now so widely used forvarious industrial operations. The invention further relates toimprovements upon the type of loader disclosed in my prior co-pendingapplication Serial No. 692,482 filed August 23, 1946, and now Patent No.2,517,582 issued August 8, 1950.

As disclosed in that application the loader comprises a wheel borneframe mounted upon a tractor of any conventional style and type andforming a pivot support for the rear end of a vertically swingable andforwardly extending boom assembly. The load carrier, whether it be afork, a shovel or whatever, is then tiltably mounted upon the forwardend of said boom assembly and by the use of suitable hydraulic liftingrams the boom assembly is swung upwardly and downwardly tocorrespondingly position the load carrier. In addition, provision ismade for adjusting and controlling the tilt angle of the load carrierwith respect to the boom assembly and to the ground so that in theoperation of a bucket, for example, the same may be tilted back to holda load in place as it is elevated and then tilted forwardly to dischargethe load whenever and wherever required.

My present invention has as its primary object the improvement oftilting mechanisms of this kind designed not only to simplify theirconstructionbut to facilitate the control of the load carrier levelunder all working conditions. A further object is to provide tiltingmechanism which may be adjusted to bring about a parallel-motioneifect'such as to maintain the load carrier at a pre-selected tilt angleas it is raised and lowered but with complete and independent controlsuch as to readily tilt the carrier to any desired angle at any time.Particularly in the case of material handling buckets it is furthermoredesirable to tilt them sharply forward in order to quickly andcompletely discharge their contents and it is a further important objectof my present invention to provide a tilting mechanism which willoperate in this fashion but without at any time becoming ineffective tocontrol the bucket angle or return it from its sharply tilted dumpingangle.

These and other more detailed and specific objects will be disclosed inthe course of the following specification, reference being had to theaccompanying drawings, in which- Fig. 1 is a side elevation of a loaderand tilting mechanism according to my present inven- 2 tion'showing thesame as mounted upon a tractor and as operating a material handling:bucket which is'shown in alowered position.

Fig. '2 is a plan view of the assembly shown in Fig. 1.

Fig. 3 is a side view similar to Fig. 1 but on a reduced scale andshowing the bucket as elevated as well as tilted sharply forward to adumping position.

Fig. 4 is an enlarged fragmentary detail. perspective view of the jointin the tilting link which permits the bucket to be tilted to the sharpdumping angle shown in Fig. 3.

Referring now more particularly and by reference characters to thedrawing, A designates generally one conventional style of tractor towhich the loader of my invention may be applied and it is, of course, tobe understood that by minor structural and framing changes the loadermay be adapted to installation and use upon most any well knowncommercially available type tractor The tractor here shown for examplehas the usual engine and chassis assembly B which is supported upon reartraction wheels C and dirigible front wheelsD with a rearwardlylocatedoperators station indicated at E. Such other parts of thisconventional tractor assembly as necessary to an understanding of thepresent invention will be referred to in the course of thisspecification.

The loader assembly per se comprises a main or mounting frame indicatedgenerally at [0 which is rigidly attached to the tractor in any suitablefashion. So far as material to the present disclosure it may be notedthat this frame 10 comprises side beams ll disposed forwardly andrearwardly alongside the engine-chassis assembly B, and adjacent thetraction wheels C, but inwardly thereof, the side beams l I supportgenerally upright support bars l2. These support bars are suitablybraced to the frame assembly Ill and at their upper ends support a maincross shaft [3 which operates as'the rear pivot for a boom assembly,designated generally at M. This boom assembly 14 comprises main sidebars [5 provided at their rear ends with tubular bearings IE to pivotupon the shaft l3 and these sidebars l5 are further rigidly trussed andcross connected as designated throughout at H. The boom assembly extendsforwardly of the tractor for some distance, with the side bars l5located at opposite sides of the tractor radiator F, and for theprojection of the radiator I provide a shield i8 which is suitablysecured to the main frame assembly Hi. This shield 18 has upright rubplates l9 upon its sides and the boom side bars l5 arev provided withinwardly projecting guide yokes 20 which may engage said rub plates. Theforward end of the boom assembly I4 is swung vertically with referenceto the tractor and the ground by means of hydraulic lift rams 2| locatedone at each side of the tractor. The rams 2| comprise cylinders 22pivotally supported at their lower ends upon a transverse pin 23 carriedby heavy hanger plates 24 depending from the side beams of the frame land further include upwardly extending and extensible plungers 25pivotally attached at 25 to the side bars l of the boom. The arrangementis thus obviously such that the admission of fluid under pressure to thelower ends of the cylinders 22 will thrust the plungers upwardly andcorrespondingly swing the forward end of the boom in the upwarddirection. When the fluid is permitted to return from the lower ends ofthe cylinders 22 the boom assembly may swing downwardly again by forceof gravity, or if preferred the rams 2| may be of the double actingvariety, in which case fluid will be admitted to the upper ends of thecylinders in order to forcefully move the boom assembly in the downwarddirection. Fluid for this operation of the rams 2| may, of course, besupplied from a pump (not shown) operated by the tractor engine, but theprecise details of hydraulic systems of this nature are so well known tothose skilled in the art as to require no further description herein.

While the loader may be used with various load carriers and work holdingdevices, according to the nature of the work to be performed, I haveshown it herewith as equipped with a material handling bucket 21 havinga curved back 23 terminating in a forwardly extending bottom 29 formingan edge which may be thrust into a pile of material in order to pick upa load thereof. The shovel is, of course, closed at its ends or sidesbut open across the front and it will therefore be understood that thebucket must be held at such an angle as to keep its load or material inplace until it is tilted forwardly for dumping its contents. For thisreason the bucket is tiltably mounted upon the boom assembly l4 and hason its lower rear sides spaced bracket pairs 3| between which tubularbearings 32 upon the forward ends of the side bars l5 are disposed. Across shaft 33 is then placed through the brackets 3| and bearings 32establishing a pivot connection such as to cause the shovel to be raisedand lowered with the forward end of the boom, but about which connectionthe bucket may be tilted in upright, forwardly and rearwardly extendingplanes. To prevent lateral sway the forward ends of the side bars l5 ofthe boom assembly are rigidly connected by a torque tube 44 adjacent thepoint where the tilting connection is made to the bucket, as best shownin Fig. 2.

According to my present invention, I provide mechanism for tilting,adjusting, and holding the bucket 21, or other load carrier, and thesame comprises a triangular or three cornered crank plate 35 which ispivotally attached at 36 by one corner to a side bracket 31 rigidlysupported in any suitable manner by the main frame In. While I hereindescribe only one complete tilting mechanism as located at one side onlyof the loader, it is to be understood that it may be duplicated upon theopposite side as desired and as may be required in a machine forparticularly heavy duty. In fact, in Fig. 2 I show tilting mechanisms atboth sides of the machine and indicate corresponding parts of each byidentical reference characters. The pivot 36 for the crank plate 35 islocated outwardly, forwardly and downwardly with respect to the rearboom pivot |3|5 and the crank plate has a second relatively forwardlylocated corner to which I pivot at 38 the plunger 33 of tilting ram 46.Like the lifting rams this tilting ram has a cylinder 4| which ispivotally attached at its lower end to the same cross pin 23 supportingthe lifting rams. Thus it will be evident that the selective admissionof fluid to opposite ends of the tilting ram cylinder 4| will upwardlyproject or downwardly retract its plunger 39 to rock the crank plate 35about its pivot 36. There results then a swinging forward end rearwardmotion of the third and upper corner of the crank plate as will beclearly apparent. To best accommodate the pivot connection 38 for thetilting ram plunger the adjacent corner of the crank plate is bifurcatedat 42. This forwardly and rearwardly swinging upper end of the crankplate 35 is connected to the bucket 21 by means of a tilting link,indicated generally at 43. This link extends in a forwardly andrearwardly angling position and at its rear end is pivotally attached at44 to the crank plate. The forward end of the tilting link is thendisposed between brackets 45 upon the upper rear side of the bucket 2'1and pivotally attached thereto by means of a connector pin 43. It willnow be understood that operation of the tilting ram 40 to swing thecrank plate 35 will move the link 43 forwardly or rearwardly andcorrespondingly tilt the bucket 27 about its pivots 33. I am thusenabled to control the tilt angle of the bucket, or other load carrier,with ease and precision and by means of a construction which isextremely simple. Furthermore, the construction has the distinctadvantage of providing a so-called self-leveling effect upon the bucketsuch as to cause the bucket to maintain any pre-selected tilt angle asit is raised and lowered by the boom assembly. This effect is broughtabout by the parallel-motion of the side bars l5 of the boom assemblyand the tilting link 43. By reference to Fig. 1 it will be readilyapparent that the crank plate 35 may be adjusted to position orreference the pivot 44 to the boom assembly pivot |3|e to exactly theangle and spacing between the bucket pivots 33 and 46, or the relationbetween these four pivot points may be so adjusted that the bucket willbe tilted back as it is elevated in order to maintain its load againstunwanted discharge. Extremely precise control and adjustment ispermissible by the link mechanism described and the control is furtherfacilitated by the provision of control handles 41 and 48 located sideby side, convenient to the operators station E, so that both or eithermay be grasped or manipulated by the right hand of the operator. Thesehandles are connected to the respective control valves (not here shown)which regulate the admission of fluid to the lifting and tilting ramsand in connection with this phase of the operation it is to be notedthat the same tilt then lift effect may be obtained as defined andclaimed in my co-pencling application hereinbefore iden tified.

The forward tilt angle of the bucket 21 would be limited by the use ofan inflexible tilting link 43 by the fact that the bucket could not thenbe permitted to go past a point at which the pivot 46 would pass deadcenter with reference to the pivots 33, since otherwise the bucket couldnot then be pulled back to its normal position. As an important furtherand correlative featur of my present invention-Itherefore provide thetilting link 43 with what may be termed a buckle joint .adjacent itsforward end as will now be described. 'In actuality the link 43comprises an elongated rear section which enters at its forward endbetween the bifurcated sides 49 of a shorter forward link section 43a. Across'pin 50 joins the sections at some'distance rearwardly of thebucket forming a pivot joint about which the link. may fold or buckleinan upwarddirection. Downward buckling motion is prohibited, however,by the provision upon the sides 49 of a stop flange 5| which overliesthe forward end of the main link section rearwardly of the pivot pin 50.The forward link section 43a normally is held in alignment with theremainder of the link by means of a retractile coil spring 52 stretchedbetween lugs 53 and 5 3 upon the link sections. This buckle joint isfurthermore so located with reference to the bucket that as the sametilts forwardly to its dumping position a contact member or shoe 55carried upon one of the brackets 3| will meet the underside of theforward link section 43a ahead of the pivot pin 50. As this contactoccurs the link will be buckled or folded upwardly as clearly shown inFig, 3 to permit the bucket to tilt considerably further for wardwithout losing control over the return of the bucket. This is, ofcourse, for the reason that a rearward pull upon the tilting link willexert a force in a line substantially upon the pivots 33 as is necessaryin order to pull the bucket toward its level position. The upwardbuckling motion about this joint is limited by a U-shaped stop yoke 5%,the sides of which are secured to the rear ends of the forward linksection 43a rearwardly of the pivot pin 59. As most clearly shown inFig. i this stop yoke 58 has a closed lower end 5? adapted to contactthe lower edge of the main rear portion 43 of the link and thus operateto limit the relative upward folding motion.

It will be apparent from the foregoin that I have thus provided atilting and positioning mechanism for load carriers of loaders of thegeneral nature described which is simple in construction and operation,and permits all of the necessary adjustments of the carrier which may beadvantageous in various operations to be carried out under theconvenient control of the operator.

It is understood that suitable modifications may be made in thestructure as disclosed, provided such modifications come within thespirit and scope of the appended claims. Having now therefore fullyillustrated and described my in vention, what I claim to be new anddesire to protect by Letters Patent is:

1.For a vehicular loader of the character described having a frame, aboom assembly pivoted to the frame and extending forwardly therefrom,means for swinging the forward end of the boom upwardly and downwardly,and a load carrier pivoted on the forward end of the boom assembly fortilting movements forwardly from a loading position to a dumpingposition; the improvement which comprises a tilting mechanism for theload carrier and including an operating member on the frame, a tiltinglink pivoted at its rear end to said operating member and pivoted at itsforward end to the load carrier, the said link including front and rearsections and means pivoting these sections together for relativebuckling movements whereby in the dumping position of the load carrierthe 6 link will buckle and the carrier "will tilt past-a dead centerposition with reference to itspivot connection to the boom assembly, andmeans for limiting said buckling movements of the link sections wherebythe linkwill be operative to push the load carrier to its dumpingposition.

'2. For a vehicular loader of the character described having a frame, aboom assembly pivoted to the frame and extending forwardly therefrom,means forswingingthe. forward end of the boom upwardly and downwardly,and a load carrier pivoted on the forward end of the boom assembly fortilting movements forwardly from a loading position to a dumpingposition; the improvement which comprises a, tilting mechanism for theload carrier and including an operating member on the frame, a tiltinglink pivoted at its rear end to said operating member and movableforwardly and rearwardly thereby, means pivoting the forward end of thelink to the load carrier above its pivot-connection to the boom, saidlink comprising front and rear sections pivotally connected for relativeupward and downward buckling movements, means on one link sectionengaging the other to prevent downward buckling movement, and means onone link section engaging the other to limit upward buckling movementwhereby the link will provide positive control over the load carriereven when buckled.

3. For a vehicular loader of the character described having a frame, aboom assembly pivoted to the frame and extending forwardly therefrom,means for swinging the forward end of the boom upwardly and downwardly,and a load carrier pivoted on the forward end of the boom assembly fortilting movements forwardly from a loading position to a dumpingposition; the improvement which comprises a tilting mechanism for theload carrier and including an operating member on the frame, a tiltinglink pivoted at its rear end to said operating member and movableforwardly and rearwardly thereby, means pivoting the forward end of thelink to the load carrier above its pivot connection to the boom, saidlink comprising front and rear sections pivotally connected for relativeupward and downward buckling movements, means on one link sectionengaging the other to prevent downward buckling movement, means on onelink section engaging the other to limit upward buckling movementwhereby the link will provide positive control over the load carriereven when buckled, and a spring connected between the link sections toresist upward buckling at their pivot connection.

4. For a vehicular loader of the character described having a frame, aboom assembly pivoted to the frame and extending forwardly therefrom,means for swinging the forward end of the boom upwardly and downwardly,and a load carrier pivoted on the forward end of the boom assembly fortilting movement forwardly from a loading position to a dumpingposition; the improvement which comprises a tilting mechanism for theload carrier and including an operating member on the frame, a tiltinglink pivoted at its rear end to said operating member and movableforwardly and rearwardly thereby, means pivoting the forward end of thelink to the load carrier above its pivot connection to the boom, saidlink comprising front and rear sections pivotally connected for relativeupward and downward buckling movements, means on one link sectionengaging the other to prevent downward buckling movement, means on onelink section engaging the other to limit upward buckling movementwhereby the link will provide positive control over the load carriereven when buckled, and means on the load carrier for engaging theforward link section as the bucket tilts and forcing it upward to bucklethe link sections.

LE GRAND H. LULL.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Butler Aug. 12, 1924 Guignard et al. May 16, 1944 Arps June27, 1944 Watson Sept. 10, 1946 Drott et a1 Sept. 20, 1949 Arps Aug. 1,1950 McNamara, Jr. July 15, 1952

